I would respectfully disagree about the .40 over the .45. Although the .40 is a smaller caliber i think that the .40 has snappier, more uncomfortable recoil. A .45 is a big old slug, but it is slow moving and usually comes in better, full size pistols. I think that makes it much more comfortable to shoot and shoot well. Recoil is 90% mental though so maybe I'm the only one that feels that way. Is the pistol going to be for concealed carry? If so it might be worth it to give up a little "shootability" to gain a little "carry-ability" in a compact pistol, and you will probably find a better selection of compact pistols in the 9mm-.40 range. Although many guys get real macho attitudes about the 9mm being a "wimpy" round, in most defensive shooting situations i doubt you would be able to appreciate the difference between the two, after the number one rule to winning a gunfight is "have a gun".